Evidently my brain works differently to yours, because nobody else thinks it is at all enforceable.
Indeed, in particular in the meaning of "nobody else".
The top people at every European CAA which anybody has asked haven't got a clue what the words mean, either.
There is some lack of clarity in the definition of "Operator" and the definition of "resident". I agree. But this doesn't mean that suddenly the entire regulation is void. The most easily dismissed is the residency issue. For 95% of FRA pilots I would imagine there is no lack of clarity as to whether they are resident in the EU or not. For those in the 5%, I imagine there are methods to resolve this uncertainty. An obvious one would be to present the case to an NAA and get their agreement, and if you don't like their verdict, you can litigate - ie. in much the same way that residency questions are resolved for tax purposes.
On the operator question, this forum and the N-reg regulation isn't, amazingly enough, the first time this question has been raised. It certainly has been a matter of all sorts of case law in the USA, for Part 91, Part 91 Supart K (Fractional) and Part 135. The circumstances in which a person is deemed to have operational control of an aircraft are reasonably clear and I don't see how some trust arrangement could ever be used for a European beneficiary or shared beneficiary to ever claim he did not have operational control, except through some elaborate and self-evidently false construct. If one ever found a US trustee willing to be party to something so dumb (given the liabilities it carries) I would imagine they were essentially crooks. You can imagine what sort of person would offer such services and then you have to ask whether you trust them as owners of your $500k Cirrus or whatever. But don't take my word for it - ask a reputable trustee outside the EU if they would be willing to claim to have operational control of your aircraft and execute both the legal paperwork and day-day 'communications' needed to substantiate that. You have been writing about this possible "solution" for years now. I bet you that you won't actually find anyone sensible willing to do it. Go on, ask around.
Anyway, I am an engineer, and I look for solutions. This also means I don't easily bend over forwards to get shafted, especially when it is proposed by a bunch of faceless shysters in Brussels.
I bought my ~ £10,000 insurance policy
earlier this year (learning absolutely nothing useful in the process) but that
isn't going to make me go native.
I am not proposing anyone "go native" or "bend over". I also look for solutions, but I evaluate them too, otherwise they are not solutions but delusions. Your engineering is faulty if you think "enforceability" is a solution to anything in respect of FRA.
This is not to say there aren't genuinely grey areas. Someone who lives half their time in the US vs EU etc. Of course, one would hope a sensible solution could be found that is fair to such a person. But for the majority of FRA operators for whom EU residency isn't a grey area, and who have no genuine connection to a genuine non-EU operator (eg. a company or private owner for whom they fly) the greyness is not meaningful IMHO.